To transport natural gas from production sites to consumers, pipeline operators install large compressors at transport stations along the pipelines. Natural gas pipeline networks connect production operations with local distribution companies through thousands of miles of gas transmission lines. Typically, reciprocating gas compressors are used as the prime mover for pipeline transport operations because of the relatively high pressure ratio required. Reciprocating gas compressors may also be used to compress gas for storage applications or prior to transport in processing plant applications.
Reciprocating gas compressors are a type of compressor that compresses gas using a piston in a cylinder connected to a crankshaft. The crankshaft may be driven by an electric motor. A suction valve in the compressor cylinder receives input gas, which is then compressed by the piston and discharged through a discharge valve.
Reciprocating gas compressors inherently generate transient pulsating flows because of the piston motion and alternating valve motion. Various devices and control methods have been developed to control these pulsations. An ideal pulsation control design reduces system pulsations to acceptable levels without compromising compressor performance.
A common method for pulsation control is the use of “filter bottles”, also called “pulsation filters”, placed between the compressor and the pipeline headers. These filters are typically implemented as volume-choke-volume devices. They function as low-pass acoustic filters, and attenuate pulsations on the basis of a predetermined Helmholtz response.